• Miles of uncrowded white sandy beaches extend to the horizon, separating the clear blue ocean and undulating grass-covered dunes.

    Fire Island

    National Seashore New York

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  • More Park Facilities Reopen During May 2013

    Watch Hill and Sailors Haven marinas open May 10. Limited ferry service from Sayville to Sailors Haven resumes May 13 and ferries from Patchogue to Watch Hill start on May 18. Remaining park facilities to reopen by May 25, 2013. More »

Horseshoe Crabs

Horseshoe crabs spawn on bay beaches
This fascinating sea creature has survived on earth for more than 300 million years and can be found on Fire Island's beaches.
 
 

Despite its common name, the horseshoe crab (Limulus polyphemus), is more closely related to spiders and scorpions than crabs. All are invertebrates from the phylum Arthropoda, or arthropods. This group of animals includes insects (Insecta); spiders, scorpions, ticks and mites (Arachnida, or arachnids); crabs, lobsters, shrimp and barnacles (Crustacea, or crustaceans); and the 4 world-wide species of horseshoe crabs (Merostomata). (Find out more!)

Horseshoe crabs are an ancient species. For over 300 million years (at least 100 million years before there were dinosaurs on earth) horseshoe crabs have roamed the world's oceans and and look today much as they have through the millennia.

Learn more about the natural history of horseshoe crabs.

 
Stranded horseshoe crabs are sometimes returned to the sea on the next high tide. Oftentimes, what looks to be a horseshoe crab is really the molt or exoskeleton shed during growth.

Stranded horseshoe crabs are sometimes returned to the sea on the next high tide. Oftentimes, what looks to be a stranded horseshoe crab is really the molt or exoskeleton shed during growth.

Fun Horseshoe Crab Facts

Did you know that horseshoe crabs have blue blood? The protein (hemocyanin) that carries oxygen in horseshoe crab blood contains copper. When oxygen binds to the copper, the blood turns blue. As the oxygen is removed from the copper (as the blood circulates and delivers oxygen to the tissues of the horseshoe crab) the blood becomes colorless. The protein (hemoglobin) that carries oxygen in human blood contains iron. When oxygen is bound to the iron, human blood is red. As the oxygen is removed from the iron, the blood becomes blue.

The name horseshoe crab refers to the shape of the animal. The front half of a horseshoe crab looks like a horse's hoof or a horseshoe.

 

Learn More!

For More Information

  • Horseshoe Crab: History & Biology/Shorebird Connection/Human Use/Research/Fisheries Management
    Mid-Atlantic Sea Grant Program and National Oceanic and Atmospheric Administration
  • Long Island Horseshoe Crab Network
    Dowling College
  • Horseshoe Crab: New York State Fishery and Regulations
    New York State Department of Environmental Conservation
    (Fire Island National Seashore is one of the areas now closed to the harvest of horseshoe crabs in New York)
 
 
  • Fire Island Fisheries Fire Island Fisheries

    Numerous species of fish have been recorded in the waters around Fire Island. Read More

  • Learn More About Fire Island Birds Learn More About Fire Island Birds

    Diverse habitats along the Atlantic flyway support a variety of avian species. Read More

Did You Know?

Deer standing in thicket of shrubs.

In the mid-1970s, Fire Island's deer herd consisted of only about 50 white-tailed deer. By 2005, the number was estimated to be 500-700 deer. More...